(1) Field of the Invention
The present invention relates to a lignocellulose-phenolic compound composite product and a process for the preparation of same. More particularly, the present invention relates to a lignocellulose-phenolic compound composite product in which the lignocellulose is in the form of a uniform solid solution having a high concentration thereof in the phenol compound, and which is useful as a starting material for resinous materials and other industrial materials.
(2) Description of the Related Arts
Resources produced from forests are regeneratable, and an effective recycle utilization of these resources is currently urgently required. For example, in industries using wood as the starting material, such as pulp and wood industries, the establishment of a process for an effective utilization of woody wastes generated from these industries is required. Moreover, an early development of a process for an effective utilization of agricultural wastes containing a lignocellulose substance, such as rice straw and rice hulls, is required.
Regarding an effective utilization of lignocellulose materials including wood, for example, Japanese Unexamined Patent Publication No. 57-2360 and Japanese Examined Patent Publication No. 63-1992 disclose a process in which a chemically modified lignocellulose material obtained by introducing at least one substituent into some of the hydroxyl groups in the lignocellulose molecule is dissolved in an organic solvent, and the formed solution is utilized as a starting material for various resinous materials.
Furthermore, Japanese Unexamined Patent Publication No. 60-206883 and Japanese Unexamined Patent Publication No. 60-104513 disclose a process in which a solution of lignocellulose material is utilized as a phenol compound-formaldehyde resin adhesive, and a process in which the solution is formed into a fiber.
Moreover, Japanese Unexamined Patent Publication No. 61-215676 and Japanese Unexamined Patent Publication No. 61-215675 disclose a process in which a molded body, a foamed body or an adhesive is prepared by dissolving a lignocellulose material in a solvent comprising a polyhydric alcohol or a bisphenol compound and using this solution in combination with a polyurethane, epoxy or other resin material.
Still further, Japanese Unexamined Patent Publication No. 61-261358 discloses a process in which a wood material, which is not chemically modified, is directly dissolved in a solvent comprising a phenol compound or a bisphenol compound without using a catalyst, and Japanese Unexamined Patent Publication No. 62-79230 discloses a process in which a wood material, which is not chemically modified, is directly dissolved in a solvent comprising an alcohol compound, a polyhydric alcohol compound, an oxyether compound, a cyclic ether compound or a ketone compound, without using a catalyst.
Japanese Examined Patent Publication No. 61-2697 discloses a technique of dissolving a wood flour in phenol in the presence of a mineral acid, and Japanese Unexamined Patent Publication No. 1-217070 discloses a similar technique.
Recently, the necessity for an effective utilization of waste-paper has increased, but a technique of utilizing an additional value of waste-paper as a lignocellulose material, especially converting waste-paper to a resin material, has not been developed.
The above-mentioned conventional techniques for the utilization of lignocellulose materials are defective in that the lignocellulose concentration in the product is low, for example, 30% by weight or less, generally 20% by weight or less, and therefore, the practical application field or application method is limited. Moreover, a process for preparing a product containing lignocellulose at a high concentration is not known.
In general, even if it is intended to dissolve lignocellulose in a phenol compound at a high concentration, for example, at a concentration of 50% by weight or more, a uniform solid solution composite product cannot be obtained, and accordingly, a phenol compound mixture containing lignocellulose at such a high concentration cannot be used as an industrial starting material because the quality is uneven.
In the conventional technique of dissolving a lignocellulose material in a phenol compound, the mechanism for promoting the dissolving reaction has not yet been made clear, and the development of a technique of promoting this dissolving reaction is indispensable and very important in the realizing of an industrial utilization of a lignocellulose material-phenol compound composite product.
Furthermore, the utilization of waste-papers is now important, and the development of the use of waste-papers in various fields is greatly desired. Especially, a realization of a technique of converting waste-paper to a resinous material is urgently demanded.